Why is my OpenGL triangle not drawing on the screen?

I am currently following this tutorial to create a simple game engine, but I am doing it using SDL and C++. I am stumped, however, because I can't get a triangle to draw on the screen, and I'm getting no errors from OpenGL. I have read tens of questions regarding the same problem, but I have already implemented the solutions to those problems (missing VAO, missing shaders, wrong size given to glBufferData). I'm only seeing a one-coloured window.

My shaders are defined like this:

#version 330 core layout(location = 0) in vec3 position; void main() { gl_Position = vec4(position, 1.0); } 

and

#version 330 core precision highp float; out vec4 frag_color; void main() { frag_color = vec4(0.0, 1.0, 1.0, 1.0); } 

and I load/use them like this:

void Shader::add_program(const std::string& shader_code, GLenum shader_type) { const GLuint shader = glCreateShader(shader_type); if (shader == 0) { throw std::runtime_error{"Could not create shader"}; } if (shader == GL_INVALID_ENUM) { throw std::runtime_error{"Invalid shader type: " + std::to_string(shader_type)}; } const GLchar* programs[1]{shader_code.c_str()}; const GLint lengths[1]{static_cast<GLint>(shader_code.length())}; glShaderSource(shader, 1, programs, lengths); glCompileShader(shader); // Error check using glGetShaderiv glAttachShader(shader_program, shader); } void Shader::compile_shader() { glLinkProgram(shader_program); // Error checks using glGetProgramiv } void Shader::bind() { glUseProgram(shader_program); } 

Finally, I have the vertices of the triangle stored like this (Math::Vector3 is just a POD struct with three floats):

std::vector<Math::Vector3> vertices{ {-1.0, -1.0, 0.0}, {0.0, 1.0, 0.0}, {1.0, -1.0, 0.0} }; 

and the init/draw code is:

Mesh::Mesh(const std::vector<Math::Vector3>& vertices) { size = vertices.size(); glGenVertexArrays(1, &vao_id); glBindVertexArray(vao_id); glGenBuffers(1, &vbo_id); glBindBuffer(GL_ARRAY_BUFFER, vbo_id); glBufferData( GL_ARRAY_BUFFER, size * sizeof(Math::Vector3), vertices.data(), GL_STATIC_DRAW ); } void Mesh::draw() const { glBindVertexArray(vao_id); glBindBuffer(GL_ARRAY_BUFFER, vbo_id); glEnableVertexAttribArray(0); glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, nullptr); glDrawArrays(GL_TRIANGLES, 0, 3); glDisableVertexAttribArray(0); } 

On every frame I first clear the window, then call the shader's bind method and then the draw method of the mesh.

Any help is highly appreciated, as I have been trying to tackle this for a long time now!